Author: Harry Guinness / Source: howtogeek.com
Lenses aren’t just dumb tubes that you attach to your camera; they manipulate light in complex ways. One of the side affects of this is optical distortion. Let’s look at it in more detail.
You are most likely to notice optical distortion in your images when you are taking photos of things with straight lines—like buildings.
What’s actually a straight line in real life might appear curved in your photo. You can see this with the window frame in the example below. I’ve added some guidelines to make the distortion easier to see. Note how the wooden slats bow slightly, especially as you move farther from the center of the photo.
Optical distortion is distinct from perspective distortion, which is where different lenses with different focal lengths give different fields of view and display foreground and background objects differently. For more on perspective distortion, check out our article on the normal focal length.
RELATED: What Is a “Normal” Camera Lens?
There are two main kinds of optical distortion: barrel distortion (seen above) and pin cushion distortion. Let’s look at each in turn.
Barrel Distortion
With barrel distortion, straight lines appear to bend outwards from the center of the image. It normally occurs when you shoot with a wide angle lens, but you’ll see the same effect with other, longer lenses in certain circumstances. An exaggerated version of the distortion pattern looks like this.
What’s happening is that the magnification of the image decreases as you move further towards its edges, which gives the effect of bending lines. It’s called barrel distortion because the image looks like it’s been mapped onto a sphere or barrel. You can really see that effect in the GIF below.
Barrel distortion is the most common kind of distortion you’ll run into, especially if you shoot with wide angle lenses. While it’s possible to adjust it using Photoshop or Lightroom, you’ll never get rid of it entirely, since it’s a property of the lenses you’re using. Professional architecture photographers spend thousands of dollars on wide angle lenses that don’t have it for a reason.
The biggest problem with barrel distortion isn’t what it does to straight lines in landscape or architectural photos, but what it does to portraits. In the image below, you can see my nose looks weirdly huge and my—normally…
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